#!/usr/bin/python
# Filename: class_init.py
class Person:
  def __init__(self, name):
    self.name = name
  def sayHi(self):
    print 'Hello, my name is', self.name
p = Person('Swaroop')
p.sayHi()

Hello, my name is Swaroop

#!/usr/bin/python
# -*- coding: UTF-8 -*-
class Singleton(object):
  __instance = None            # 定义实例
 
  def __init__(self):
    pass
 
  def __new__(cls, *args, **kwd):     # 在__init__之前调用
    if Singleton.__instance is None:  # 生成唯一实例
      Singleton.__instance = object.__new__(cls, *args, **kwd)
    return Singleton.__instance

#!/usr/bin/python
# -*- coding: UTF-8 -*-
class Fruit(object):
  def __init__(self, color = "red", price = 0):
    self.__color = color
    self.__price = price
     
  def __getattribute__(self, name):        # 获取属性的方法
    return object.__getattribute__(self, name)
 
  def __setattr__(self, name, value):
    self.__dict__[name] = value
 
if __name__ == "__main__":
  fruit = Fruit("blue", 10)
  print fruit.__dict__.get("_Fruit__color")    # 获取color属性
  fruit.__dict__["_Fruit__price"] = 5
  print fruit.__dict__.get("_Fruit__price")    # 获取price属性

#!/usr/bin/python
# -*- coding: UTF-8 -*-class FruitShop:
   def __getitem__(self, i):   # 获取水果店的水果
     return self.fruits[i]   
if __name__ == "__main__":
  shop = FruitShop()
  shop.fruits = ["apple", "banana"]
  print shop[1]
  for item in shop:        # 输出水果店的水果
    print item,

banana

apple banana

#!/usr/bin/python
# -*- coding: UTF-8 -*-
class Fruit:   
  '''Fruit类'''        #为Fruit类定义了文档字符串
  def __str__(self):     # 定义对象的字符串表示
    return self.__doc__
 
if __name__ == "__main__":
  fruit = Fruit()
  print str(fruit)      # 调用内置函数str()出发__str__()方法，输出结果为:Fruit类
  print fruit         #直接输出对象fruit,返回__str__()方法的值，输出结果为:Fruit类

#!/usr/bin/python
# -*- coding: UTF-8 -*-
class Fruit:
  class Growth:    # 内部类
    def __call__(self):
      print "grow ..."
 
  grow = Growth()   # 调用Growth()，此时将类Growth作为函数返回,即为外部类Fruit定义方法grow(),grow()将执行__call__()内的代码
if __name__ == '__main__':
  fruit = Fruit()
  fruit.grow()     # 输出结果：grow ...
  Fruit.grow()     # 输出结果：grow ...